Combination of two plant extracts in the synthesis of AgNp against plant pathogen Xanthomonas spp.

Abstract

Nanoparticles synthesized from plant sources have attracted a lot of attention for their eco-friendly and efficient antimicrobial properties. In this study, silver nanoparticles (AgNPs) were synthesized utilizing a combination of two different plant extracts, viz., Aegle marmelos and Betula utilis. The biosynthesis was carried out by mixing the plant extracts in different proportions with a silver precursor solution, resulting in the creation of stable AgNPs. The physicochemical characterization of AgNPs revealed a zeta potential of − 14.5 mV, indicating good colloidal stability, and a particle size determined using Dynamic Light Scattering (DLS), with FESEM used for morphological characterization showing predominantly cubic particles UV-Vis spectroscopy analysis exhibited a characteristic surface plasmon resonance (SPR) peak at 419 nm, confirming the production of silver nanoparticles. The FTIR spectra showed a major peak at 3323.35 cm−1 corresponding to phenolic O–H stretching and amine N–H stretching, whereas X-ray diffraction confirmed the nanocrystalline, face-centered cubic (FCC), structure of metallic silver through distinctive diffraction peaks that match the (111), (200), (220), (311) and (222) planes. The antibacterial activity of the synthesized nanoparticles from a 1:1 combination of two extracts was assessed against Xanthomonas species using the agar well diffusion method. Notably, at different concentrations, the 1:1 combination of AgNPs exhibited a greater zone of inhibition (ranging from 0.8 to 19.2), showed antibacterial activity against tested microorganisms that was either equal to or greater than that of streptomycin, the standard antibiotic used as a positive control. These results imply that biosynthesized silver nanoparticles have strong antibacterial activity and may be a useful substitute for traditional antibiotics in the management of diseases caused by Xanthomonas spp.